Electric stop motion for knitting machines



Sept. 13, 1932. A. CRAWFORD ELECTRIC STOP MOTION FOR KNITTING MACHINESFiied pril 1, 1950 5 Sheets-Sheet 1 Sept. 13, 1932.

A. CRAWFORD 1,877,647 ELECTRIC STOP MOTION FOR KNITTING MACHINES 7 FiledAprill, 19 0' v 5 Sheets-Sheet 2 Sept. 13, 1932. A. CRAWFORD ELECTRICSTOP MOTION FOR KNITTING MACHINES 5 Sheets-Sheet Filed April 1, 1930\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\w u71s\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\- 1 v I, a v w Patentedsept. 13,1932.

UNITED STATES" PATENT OFFICE ALFRED CRAWFORD, 01' NEW BRUNSWICK, HEWmmmassmxon '10 GRLWI'ORD nanuuc'rmmwe 001mm, or .02 new mass:

NEW BRUNSWICK, NEW JERSEY, A (XJRPORATION m0 STOP IO'IIOR FOR KNITTINGApplication fled April 1,3930. man Re. new.

above mentioned patent to a stop motion of the general character shownand described in a rior United States patent to Frank Craw 0rd, Sr., No.1,684,308, datedSeptember 11, 1928.

The object of the present invention is to provide a device which willhave a greater scope of utility and greater sensitiveness than thedevice shown in the first mentioned patent and at the same time be of arather simple construction.

The nature of the construction of the de-' vice shown in Patent No.1,417,914 limits the utility of the device to machines using relativelyheavy knitting threads, but by the adaptation of the principles thereofto the extremely sensitive device disclosed in Patent No. 1,684,308threads of the lighter weights may be employed, for example, threads ofthe nature known in the knitting art as two thread silk, or itsequivalent in rayon or other threads.

The device shown in Patent No. 1,417,914, by the nature of itsconstruction, is limited to machines employing four knitting threads, ormultiples of two, whereas by adapting the general lprinciples of such adevice to the apparatus s own in Patent No. 1,684,308 any desired numberof knitting threads may be employed. I

Another object of the resent invention is to provide means where y theelectric current is automatically cut oil from the entire device evertime the sto motion is tripped, either by t e breaking o a knittingthread, a condition causing abnormal tension to be applied to one ormore of the lmit'ting threads, or by abnormal 'slackenin of any of thethreads which may 'oceurw ile a machine is standing idle for a prolongedperiod of time, such as overnight or between two regular workingperiods.

In the drawing of the present application:

Fig. 1 is a perspective view of the diop mo- P1011 embodying thefeatures of the present mventlon;

Fig. 2 is a plan view of the upper control head which is adapted to beactuated by abnormal tension conditions arising in the knittinlgthreads; 1

ig. 3 is a side elevation of the mechanism shown in Fig. 2 with thecasing broken away for the purpose of illustration;

Fig. 4 is a fragmentary sectional elevation taken on the line 4'4,

Fig. 5 is a plan view of the lower control head adapted to be actuatedby the breaking of a knitting thread or by excessive slacknessdeveloplng therein;

' Fig. 6 is a side elevation of the mechanism shown in Fig. 5, with thecasing broken away for the purpose of. illustration;

Fig; 7 is a perspective view of the safety swatc mechanism shown inFigs. 5 and 6; an

Fig. 8 is-awiring diagram.

As shown in Fig. 1, the device in general comprises a standard 10rigidly secured to and projecting upwardly from the main bed plate 1 ofa conventional type of knitting machine, which is provided with asuitable lever 2 adapted for shifting the drivin belt of the knittingmachine from the tig t to the loose pulley thereof, when the stop motionis actuated, to stop the machine.

Mounted on the upper end of the standard 10 is the lower control head orstop motion 11, which comprises a casing 12 and a cover 13 therefor.

Mounted in the cover 13 of the lower control head 11 and substantiallyin axial alignment with the standard 10 is a second or upper standard14, which constitutes a con- In each of the stumps 18 is rotatablymounted a trip rod 21 having a lever 22 at its outer end adapted toengage the underside of the trip finger 20. On the inner end of eachtrip rod 21 is a double ended lever 23, one end of which is (providedwith a crank 24 and to opposite en of which 1s secured one end of asprin 25.

The opposite end of the spring 25 is socured to the outer end of atension regulating arm 26, pivoted at 27 to a plate 28 disposesubstantially parallel to a base plate 29 which is secured in the bottomof the caslng 16. The plate 28 is spaced apart from the plate 29 by anintermediate hub 30.

Secured in the hub 30 is a 0st 31, in the upper end of which is rotataly mounted a pivot stud 32 for and secured to a horizontally disposedactuating disc 33.

The disc 33 is rovided with an interrupted depending age 34, which isnotched at spaced intervals, as indicated at 35, 35, into each of whichprojects one of the cranks 24 of the levers 23 on the inner ends of thetrip rods 21.

The springs 25 tend to turn the rods 21 in a clockwise direction, asviewed from the interior of the casing 16, which causes the levers 22 toturn the trip fingers upwardly about their pivots 29, the trip fingersengaging abutments 36 which maintains the whole chain of elements in apredetermined operative position.

The interrupted flan e 34 of the disc 33 is provided with a notch 37 inwhich is dis posed the upper end of a lever 38. The lever 38 is pivotedat 39 to a bracket 40 which is secured to the base plate 29 in thebottom of the casing 16.

The lever 38 at one side of its pivot 39 is provided with acounterbalance 41, which tends to turn the lever 38 about its pivot andthereby turn the disc 33 in a clockwise direction, as viewed from above,which maintains the sides 42 of the disc notches 35 in contact with thecranks 24 of the trip rods 21.

At the opposite side of its pivot 39, the lever 38 is provided with alateral projection 43, at the outer end of which is secured aninsulating block 44. In the insulating block 44 is secured an invertedU-shaped contact element 45. The contact element 45' is provided with apair of spaced depending contacts 46, 46, which respectively arepositioned in wells 47, 47 formed in an insulating block 48. Theinsulating block 48 is adjustably mounted in the bottom of the casing16.

In each of the wells 47 is provided a suitable quantity of mercury orother fluid-like substance 50 capable of efiiciently conducting electriccurrent.

As shown in Fig. 4, the lower ends of the contacts 46, 46 are disposedslightly above the surface of the conducting medium 50 in each well.The. tension of the springs 25, 25 and the counterbalancing of the lever38 is so minutely adjusted that these contacts are normally held in theposition shown when the knitting machine is in operation, the minutecounterbalancing of the lever 38 being augmented by a light spring 51,shown in Figs. 2, 3 and '4.

The insulating block 48 passes through suitable openings formed in thebase plate 29 and the bottom of the casin 16 and is provided outside thecasin with a laterally extending projection 52 t rough which passes asupporting screw 53. The screw 53 is threaded into the bottom of thecasing 16, the base plate 29, or both, for raising the block 48 in thecasing and thereby adjusting the position of the upper surface of theconducting mediums 50, 50 relative to thelower ends of the contacts 46,46. A control screw 54 is threaded through the extension 52 of the block48 and bears against the lower side of the bottom of the casing 16,whereby the block 48 may be secured-in its adjusted position or moved inan opposite direction in making the adjustment.

Secured to the base plate 29, adjacent the insulating block 48, orformed integral with the said block 48, is another insulating block 55which is provided with stationary contacts 56 and 57. These fixedcontacts extend into the wells 47 47 and into the conducting me diumtherein, at all times.

The fixed contacts 56 and 57 are respectively connected tocurrent-conducting wires 58 and 59, for purposes hereinafter set forth.The upper standard 14, in the present instance, is hollow and the wires58 and 59 pass from the casing 16 of the upper control head 15 throughthe upper standard 14 to the lower control head 11.

The lower control head 11, as above noted, comprises the casing 12 andcover 13. As shown in Fig. 6, the wires 58 and 59 terminate in aninsulating block 60 secured to the underside of the cover 13, the wiresbeing electrically connected to suitable prongs 61 which are adaptedrespectively to enter openings 62, 62 formed in an insulating block 63secured to the side wall of the casing 12, the openings 62, 62 beingprovided with suitable spring contacts 64, 64 which engage the tips 61to make electrical contact therewith.

YVith this construction the upper part of the apparatus may be readilyremoved from the lower part thereof to facilitate shipping.

Radiating from the casing 12 of the lower control head 11 is a pluralityof arms 118 each having rotatably mounted therein a trip rod 121. On theinner end of each trip rod 121 is a crank 124 adapted to lie withinandengage one side 142 of a notch 135 formed in an interrupted dependingflange 134 of an actuating disc 133.

On the outer end of each arm 118 is a thread uide comprising astationary plate which is Uf-shaped in plan. In the respective sides 71,71 of the U-shaped plate 70 are formed slots 72, 72a.

On the outer end of each tri rod 121 is a drop lever 73 having fingers4, 74 which extend into the slots 72 formed in one of the side plates71. v

The knitting thread :2: passes between the plate 71 and the finger 74,which holds the drop lever 73 in a substantially vertical position andmaintains the trip rod 121 and the crank 124 thereon in a predeterminedoperative position.

The disc 133 is rotatably-mounted in a post 131 located in the casing12, a spring 75, which is wound about the pivot stud 132 of the disc 133and nas one end secured in the post 131 and its opposite end inengagement with a In 76 formed on the disc 133, tends to rotate t 1edisc 133 iu'a clockwise direction, as viewed from above, to hold thesides 142 of the notches 135 in contact with the cranks 124 of the triprods 118.

Secured in the bottom of the casing 12 is a base plate 129, 011 which issecured a bracket 140. Pivotally mountedat 139 to the bracket is a lever138. The upper end of this.

lever 138 lies in a notch 137 of the depending flange 134 of the disc133.

The lever 138 at one side of its pivot 139 isprovided with acounterbalance 141 and at the opposite side of its pivot with anextension 143 on which is mounted an insulating block 144. Theinsulating block 144 is provided with an inverted U-shaped contactelement 145. The contact element 145, like the contact element 45 abovenoted, comprises two depending contacts 146, 146 which extend into wells147, 147 formed in an insulating block 148.

Like the block 48 above noted, the block 148 extends through openings inthe base plate 129 and in the bottom of the casing 12, and is providedwith an extension 152 and adjusting screws 153 and 154, which functionin exactly the same manner as the screws 53 and 54 above noted.

The wells 147, 147 each contain a quantity of mercury 150, or otherelectric-conducting fluid-like substance, and projecting into theconducting medium in the wells 147, 147 respectively are fixed contacts156, 157.

The fixed contact 156 is connected by a wire 58a to the spring terminal64 in the socket 62 into whichthe tip 61 of the wire 58 extends, thusmaking a direct electrical con nection from the fixed contact 56 of theupper control head 15 to the fixed contact 156 in the lower control head11.

The fixed contact 157 is connected by a wire 159a to one terminal 160'of an electric motor which, in the present instance, is inthe form of anelectro-magnet 161 which is securely mounted in the casing 12. Thetertacts 57 and 157 are directly connected to one terminal 160 of theelectro-magnet 161, and the fixed contacts 56 and 156 are connecteddirectly with each other and with one wire 158 of a power line, theother wire 159 of the said power line being connected, through a safetyswitch 165, to the second terminal 162 of the electro-magnet 161.

The safety switch 165 comprises an insulat ing block 1650 which issecured in the casing 12. A knife switch blade 166 is pivoted at 167 tothe block 165a and normally engages at its opposite ends with contacts168 and 169, respectively, to which the ends of the split wire 159 arerespectively connected. A s ring 170 tends to open the switch 165 at altime but is restricted in its efforts by mechanism hereinafterdescribed.

Pivotally mounted at 171 on a bracket 172 located adjacent theelectro-magnet 161 is a bell-crank lever 173, one arm 174 of whichliesdirectly above the core 175 of the electromagnet. The second arm 176of the bellcrank lever 17 3' is adapted to engage an arm stop motion. Aspring 183 wound about the which is pivoted at 179 to actuating shaft182, tends to turn the shaft in a clockwise'direction at all times, toactuate the stop motion to stop the machine.

The actuating shaft 182 is rotatably mount- 2 ed at its upper, end inthe casing 12 of the 7 lower control head 11 and at its lower end in abearing 182a carried by the lower standard 10 adjacent the bed plate 1of the knitting machine.

On the lower end of the actuating shaft 182 is secured a lever 185, inthe outer end of which is slidably mounted one end of a link 186 havingan abutment 187 thereon which is engaged by the lever 185. The oppositeend of the link 186 is connected to one arm 187 of a bell-crank lever188, which is pivoted at 199 to the bed plate 1 of the knitting machine.I

The second arm of the bell-crank lever 188has a. shoulder 191 againstwhich the outer end of the belt shifter arm 2 normally bears, underressure exerted by a spring (not shown) hut which, when the lever 2 isreleased by the bell-crank arm 190 moving the knitting machine to stopthe said machine.

The safety switch blade 166 is held in operating position by a lug 195,composed of insulating material, secured to the actuating lever 181. Thelug 195 as shownin Fig. 5,

bears against one end of the switch blade 166 and holds it in engagementwith the contacts 168, 169 against the action of thespring 1 70. Whenthe knitting machine is 1n operation i the elements of the stop motionare in the rocking the trip rod 21. which through the clockwisedirection. Turning of the disc 33' to the electro-magnet 161.

crank 24, will turn the disc 33 in a counterin a counter clockwisedirectionwill rock the lever 38 about itspivot, causing the ends of thedepending contacts 46, 46 to dip into i the mercury in the wells 47, 47which completes the electric circuit to the 'electro-magnet 161.

If one of the threads :2: should break or become abnormally slack, thedrop arm 73 which is controlled by such thread will be released and willfall, thereby turning the trip rod 121 on which it is mounted. Burningof the trip rod 121 will, through the crank 124, turn the disc 133 in acounter clockwise direction, thereby turning the lever 138 about 7 itspivot, permitting the depending contacts 146, 146 to dip into themercury 150, 1 in the wells 147, 147, thus completing the c1rcu1t Whenthe electro-magnet 161 is energized, by the operation of either the disc33 in the upper control head or the disc 133 in the lower control head,as above noted, the magnet immediately pulls down on the arm 174 of thebell-crank lever 17 3, turning the said bell-crank lever 173 on itspivot 171, so that the second arm 176 thereof will strike the arm 177 ofthe latch 178. The latch 178 is thereby turned on its pivot 179, causingthe hook 180 of the latch to release the actuating arm 181 of theactuating shaft 182.

The spring 183 then turns the shaft 182 causing the lever 185 to pull onthe link 186, which turns the bell-crank 188 on its pivot 189, theshoulder, 191 being thereby removed from in front of the belt-shiftinglever 2, permitting the said lever 2 to effect a shiftingof the drivebelt from the tight to the loose pulley, as above noted.

As the actuating shaft 182 turns, the lug 195 on the lever 181 movesaway from the switch blade 166, which immediately turns about its pivotunder the influence of the spring 170, thereby breaking the electriccontact between the switch blade 166 and the contacts 168, 169.

The whole apparatus is thereby wholly dismatically reset the drop arms73, 73. The

contacts .146, 146 are at the same time removed from the mercurycontacts 150, 150.

To reset the device the actuating'shaft 182 is turned in a reversedirection by manually operating the resetting lever 196 which is'secured' to the actuating shaft 182. Such turning of the shaft 182causes the tip of the actuating lever 181 to be reengaged by the hook180 of the latch 17 8, the lug 195 again engaging the knife switch blade166 and turning it about its pivot 167 until the opposite ends of theswitch blade engage the con tacts v168, 169 respectivel it beingunderstood that the cause for t e tripping of the stop motion has beenremoved, permitting the drop levers and tension fingers to reassumetheir normal operative positions above noted.

Obviously, the magnet 161 and the latch arm 177 could be soarranged thatthe magnet would act directly on thesaid latch arm and thus eliminatethe bell-crank lever 173. This could be accomplished by positioning themagnet 161'in'a position with its axis lying in a horizontal plane ,withthe end of: the core 175 adjacent the latch arm 177. While I .havedescribed a magnet with a fixed core, obviously a movable plungersolenoid could be employed with the said plunger operatively connectedto either the arm 174 of the bell-crank lever 173 or directly to the arm177 of the latch 178.

The vertical adjustment of the mercury pots 48 and 148, relative to theends of the contacts 46, 46 and 146, 146, makes it possible to regulatethe extent of permissible ineffective relative movement between themercury contacts and the movable contacts cooperating therewith, to timethe actuation of the stop motion, and, due to the construction shown,this timing may be readily made from the outside of the casing withoutdisturbing any of the operating parts of the mechanism.

I claim:

1. In a stop motion, the combination of a plurality of thread-controlledtrip elements, an actuating disc common to all said trip elements andadapted to be actuated b any thereof, a normally open electric switccontrolled b said actuating disc and adapted to be close thereby forcompleting an electric IUD circuit in which said switch is included, toeffeet the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, and a normally closed switch included in said circuit andadapted to be opened to interrupt said circuit subsequent to the closingof the first said actuating disc.

2. In a stop motion, the combination of a plurality of thread-controlledtrip elements, an actuating disc common to all said trip elements andadapted to be actuated by any thereof, a normally open electric switchcon trolled by said actuating disc and adapted' to be closed thereb forcompleting an electric circuit in whic said switch is included, toeffect the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electric motor included in said circuit for effecting thestopping of the machine to which the stop motion is applied when thesaid circuit is closed by the normaluse ly open switch, and a normallyclosed switch included in said circuit and adapted to be opened tointerrupt the circuit upon and subsequent to the actuation of saidelectric motor.

3. In a stop motion, the combination of a plurality of threadcontrolledtrip elements, an actuating disc common to all said trip elements andadapted to be actuated by any thereof, a normally 0 en electric switchcon trolled by said actuating disc and adapted to be closed thereby forcompleting an electric circuit in which said switch is included, toeffect the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electric motor included in said circuit, an actuating lever,a latch engaging said lever, and means actuated by said motor to releasesaid latch from said lever u on the closing of the circuit by saidnormal y open switch.

4. In a stop motion, the combination of a plurality ofthread-controlledtrip elements, an actuating disc common to all said trip elements andadapted to be actuated by any thereof, a normally open electric switchcontrolled by said actuating disc and adapted to be closed thereby forcompleting an electric circuit in which said switch is included, toeffect the stopping of the machine to which the sto motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electric motor included in said circuit, an actuating lever,a latch engaging said lever, means actuated b said motor to release saidlatch from sai lever upon the closing of the circuit by said normallyopen switch, and a normally closed switch included in said circuit andcontrolled by one of said elements in a manner to be switch by the aplurality of thread-controlled tri opened to interrupt the circuitsubsequent to the actuation of the motor.

5. In a stop motion, the combination of a plurality of thread-controlledtrip elements, an actuating disc common to all said'trlp elements andadapted to be actuated b any thereof, a normally open electric switccontrolled by said actuating disc and'adapted to be closed thereby forcompleting an electric circuit in which said switch is included, toeffect the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electric motor included in said circuit, an actuating shaft,an actuating lever on said actuating shaft, a latch engaging said lever,means actuated by said motor to release said latch from said lever uponthe closing of the circuit by said normally open switch, and a normallyclosed switch included in said circuit and controlled by one of saidelements in a manner to be opened to interrupt the circuit subsequent tothe actuation of the motor.

6. In a stop motion, the combination 10f e ements, an actuating disccommon to a 1 said trip elements and adapted to be actuated by anythereof, a normally open electric switch controlled by said actuatingdisc and adapted to be closed thereby for completing an electric circuitin which said swltch is in cluded, to effect the stopping of the machineto which the stop motion is applied when an abnormal condition arises inany oi the trip-controlling threads, an electro-magnet included in saidcircuit, an actuating lever, a latch engaging said actuating lever, anda lever engaging said latch and adapted to be actuated by saidelectro-magnet to release said latch from the actuating lever.

7. In a stop motion, the combination of a plurality of thread-controlledtrip elements, an actuating disc common to all said trip elements andadapted to be actuated by any thereof, a normally open electric switchcontrolled by said actuating disc and adapted to be closed thereby forcompleting an electric circuit in which said switch is included, toeffect the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electro-magnet included in said circuit, an actuating lever,means tending to turn said lever in one direction, a retaining latch forand engaging said actuating lever, and a lever enga 'ng said latch andadapted to be actuated y said electroan actuating disc common to allsaid trip elements and ada ted to be actuated by any thereof, a normal yopen electric switch controlled by said actuating disc and adapted to beclosed thereby for completing an-electric circuit in which said switchis included, to effect the stopping of the machine to which the stopmotion is applied, when an abnormal condition arises in any of thetrip-controlling threads, an electro-magnet included in said circuit, anactuating lever, means tending to turn said lever in one-"direction,

a retaining latch for and engaging said actuating lever, and abell-crank lever having one of its arms engaging said latch and itsother arm overlying and adapted to actu ated by said electro-magnet torelease said latch from the actuating lever.

9. In a stop motion, the combination of a plurality of thread-controlledtrip elements, an actuating disc common to all said trip elements andadapted to be actuated by any thereof, a normally open electric switchcon trolled by said actuating disc and adapted to be closed thereby forcompleting an electric circuit in which said switch is included, toeffect the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electro-magnet included in said circuit, an actuating lever,means tending to turn said lever in one direction, a retaining latch forand engaging said actuating lever, a bell-crank lever havin one of itsarms engaging said latch and its other arm overlying and adapted to beactuated by said electro-magnet to release said latch from the actuatinglever, and a normally closed switch included in said circuit, meanstending to open said normally closed switch at all times, said normallyclosed switch being normally retained in its closed position byengagement with said actuating lever.

10. In a stop motion, the combination of an upper control head and-alower control head, a plurality of thread controlled trip elements ineach of said heads, an actuating disc in each head common to all andadapte to be actuated by any of the trip elements therein, an electricswitch in each head con trolled by the disc therein, an electric motorcommon to both heads and included in one side of an electric circuitwith. said switches and adapted to be controlled by either of saidswitches to effect the stopping of the machine to-which the stop motionis applied, and an automatic safety switch in and adapted to open theopposite sideof said electric circuit including the first two saidswitches and the said motor subsequent to the actuation of said motor.

11. In a stop motion, the combination of a series of pivotally mountedtrip elements, a

pivotally mounted actuating element common to all and engaged by each ofthe said trip elements, an electric switch comprising a pivotallymounted lever engaged by said common actuating element, an electriccontact carried by said switch lever at one side of its pivot,

and a -counterweight carried by the said switch lever at the oppositeside of its pivot, whereby the said pivotally mounted elements aremaintained in substantially balanced rc-.

' lation to each other.

12. In a stop motionfthe combinationof a series of pivotally mountedtrip elements, a pivotally mounted actuating element common to all andengaged by each of the said trip otally mounted lever engaged by saidcommon actuating element, an electric contact carried by said switchlever at one side of its pivot, a pair of relatively tiked electriccontacts adapted to be-engagcd by said movable contact, and acounterweight carried by the said switch lever at the opposite side ofits pivot, whereby the said pivotally mounted elements are maintained insubstantially bal actuating element, an electric contact carried by saidswitch lever at one side of its pivot, a counterweight carried by thesaid switch lever at the opposite side of its pivot,'whereby the saidpivotally mounted elements are maintained in substantially balancedrelation to each other, and an adjustable spring tension augmenting thesaid counterweight.

14. In a stop motion, the combination of a casing, a plurality ofthread-controlled trip elements extending into said casing, an actuatingdisc in said casing and common to all said trip elements and adapted tobe actuated by any thereof, an electric switch controlled by saidactuating disc for controlling an electric circuit in which said switchis included, to efiect the stopping of the machine to which the stopmotion is applied, when an abnormal condition arises in any of thetrip-controlling threads, said switch comprising an insulating blockmounted in said casing and having a well containing a suitablefluid-like electric conducting medium therein to which one side of saidcircuit is eonn a movable contact operatively connected to saiddisc andnormally lying above the surface of said conducting medium, and meansfor adjusting the said insulating block relative to the casing and tosaid movable contact therein, to regu late the extent of permissibleinefiective relative movement between'said switch elements under normaloperating conditions.

15. In a stop motion,-the combination of a plurality ofthread-controlled trip elements, an actuatingdisc common to all saidtrip elements and adapted to .be actuated'by -ny.

75 elements, an electric switch comprising a pi v I thereof, a normallyopen electric switch controlled by said actuating disc and adapted to beclosed thereby for completing an electric circuit in which said switchis included, to

effect the stopping of the machine to which the stop motion is applied,when an abnormal condition arises in any of the trip-controllingthreads, an electric motor included in said circuit, an actuating lever,a latch engaging said lever, means actuated by said motor to releasesaid latch from said lever upon the closing of the circuit by saidnormally open switch, and an arm on said actuating lever adapted toengage said disc and return the said disc and the said trip elements totheir normal positions, When said actuating lever is released from saidlatch.

ALFRED CRAWFORD.

